The molecular mechanism involved in transport of asialoglycoproteins frm the plasma to the lysosomal system of mammalian hepatocytes will be investigated. Highly purified plasma glycoproteins of knowns carbohydrate chain structure and glycopeptides derived thereof (bi- and triantennary structures) will be used. The glycopeptides will be further cross-linked to obtain a series of even morehighly clustered derivatives. Synthetic analogues of bi- and triantennary structures will be linked to protein to mimick natural glycoproteins. The rates and extents of binding, internalization, and degradation of these substances will be measured and will be related to the structural features. These experiments are designed to show the structure (e.g., degree of clustering, molecular weight etc.) required for "homing" these glycoconjugates to lysosomes. For those glycoconjugates which are internalized and externalized without degradation (i.e., diacytosis), the ability of multiple ligands to elicit heterophagy will be studied. In these studies, hepatocytes, isolated by the collagenase perfusion method, will be used, either in suspension or a monolayer cells. It is hoped that the results obtained will yield information eventually leading to clinical applications such as enzyme replacement therapy or prolonging survival time of infused therapeutic asialoglycoproteins.